The present invention relates to an improved kind of clamp for holding a key blank during cutting thereof and adapted to be used in conjunction with a key cutting machine for cutting the key blank.
Prior-art key cutting machines are known to generally include clamp in which a key blank is inserted and clamped for subsequent cutting by a milling operation aimed at imparting a desired mechanical code, i.e. the bit notch pattern, to the key blank. Two such clamps or vices are typically provided in conventional key cutting machines, including a first clamp for the key blank and a second clamp for holding an original key already having the desired mechanical code cut therein. More recent key cutting machines, however, generally employ only a single clamp for holding the key blank, since all information needed to code it, i.e. to cut the desired bit notch pattern, is selected and retrieved from an electronic storage memory and transmitted to the operating parts of the cutting machine directly therefrom.
The correct positioning of each key or key blank in its respective clamp can be obtained, according to the various types of keys involved, through the use of fixed locator provisions provided in the clamp itself or, possibly, retaining members to be selectively inserted in appropriate reference receptacles provided in the clamp for this particular purpose. The need for selectively positionable retaining, i.e. locating, members to be used in such clamps is basically due to the fact that key blanks and keys have different lengths depending on the applications in which the keys are or will be used. As far as the key or key blank itself is concerned, the tip or the rear thereof can act as a locator means or, alternatively, a shoulder of the key blank or some other reference surface of the key blank can be used as a locator means.
The use of removable locating means on the clamp carries a number of practical drawbacks with it, the most dangerous of which is represented by the operator possibly omitting to remove the locating member from the clamp before starting cutting machine operation, which could result in the machine itself undergoing serious damages. In view of doing away with such drawback, U.S. Pat. No. 6,641,339 discloses a clamp including a pair of jaws that are movable relative to each other, so as to define an accommodation in which the key is to be inserted, and a locator provision that is associable to such accommodation to hold the key clamped in position. The locator is pivotally coupled on to the body of the clamp and is provided with a groove, along which there is capable of sliding the threaded stem of a screw that enables a retaining member to be selectively locked at any one of a plurality of slots provided on the sides of the jaws.
Despite attempting to do away with the drawback referenced above, the approach disclosed in the '339 patent still calls for the use of a removable member (gauge), which must be removed before the key cutting operation is started, in view of preventing it from interfering with the operating parts of the key cutting machine, when the latter is operated. In addition, a clamp of this kind is not able to solve a number of other problems. For example, it does not reliably ensure a correct clamping of the key in the clamp itself, so as to avoid the risk of the key possibly tilting or tipping over in its accommodation. Furthermore, the clamp is not suitable for application in a key cutting machine for the cutting of so-called “laser-type” keys, which require being processed, i.e. cut, on the two major surfaces of the key blade.